Method for producing display device

ABSTRACT

In a liquid crystal display device, a first substrate includes electrical wirings and a semiconductor integrated circuit which has TFTs and is connected electrically to the electrical wirings, and a second substrate includes a transparent conductive film on a surface thereof. A surface of the first substrate that the electrical wirings are formed is opposite to the transparent conductive film on the second substrate. the semiconductor integrated circuit has substantially the same length as one side of a display screen (i.e., a matrix circuit) of the display device and is obtained by peeling it from another substrate and then forming it on the first substrate. Also, in a liquid crystal display device, a first substrate includes a matrix circuit and a peripheral driver circuit, and a second substrate is opposite to the first substrate, includes a matrix circuit and a peripheral driver circuit and has at least a size corresponding to the matrix circuit and the peripheral driver circuit. Spacers is provided between the first and second substrates. A seal material is formed outside the matrix circuits and the peripheral driver circuits in the first and second substrates. A liquid crystal material is filled inside a region enclosed by the seal material. A protective film is formed on the peripheral driver circuit has substantially a thickness equivalent to an interval between the substrates which is formed by the spacers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/057,994, filed Mar. 28, 2008, now allowed, which is a continuation ofU.S. application Ser. No. 09/126,826, filed Jul. 31, 1998, now U.S. Pat.No. 7,483,091, which is a continuation of U.S. application Ser. No.08/618,267, filed Mar. 18, 1996, now U.S. Pat. No. 5,834,327, whichclaims the benefit of foreign priority applications filed in Japan asSerial No. 07-86372 on Mar. 18, 1995, Serial No. 07-88789 on Mar. 21,1995, and Serial No. 07-88759 on Mar. 22, 1995, all of which areincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a passive matrix type or an activematrix type display device such as a liquid crystal display device, inparticular, a fashionable display device having a large occupying areaof a display portion on a substrate which is obtained by effectivelyforming a semiconductor integrated circuit for driving.

2. Description of the Related Art

Structures of a passive matrix type and an active matrix type have beenknown as a matrix type display device.

In the passive matrix type, a large number of strip type electricalwirings (row wirings) made of a transparent conductive film or the likeare formed on a first substrate along a desired direction, and striptype electrical wirings (column wirings) are formed on a secondsubstrate in a direction substantially perpendicular to the desireddirection of the electrical wirings formed on the first substrate. Thesesubstrates are arranged so that the electrical wirings formed on boththe substrates are opposite to one another.

If an electro-optical material such as a liquid crystal material that atransparent (transmittance) degree and a photoreflective-scatteringdegree are changed by a voltage, a current or the like is formed betweenthe substrates, the transparent degree, the photoreflective-scatteringdegree and the like in its intersection portion can be selected byapplying (supplying) a voltage, a current or the like between a desiredrow wiring on the first substrate and a desired column wiring on thesecond substrate. Thus, a matrix display can be performed.

In the active matrix type, row wirings and column wirings are formed onthe first substrate using a multilayer wiring (interconnection)technique, pixel electrodes are formed in those intersection portions,and an active element such as a thin film transistor (TFT) is formed ateach pixel electrode, so that a structure which controls a voltage(potential) or a current with respect to the pixel electrodes isobtained. Also, a transparent conductive film is formed on the secondsubstrate. The first and second substrates are arranged so that thepixel electrodes on the first substrate are opposite to the transparentconductive film on the second substrate.

A substrate to be used is selected in accordance with a producingprocess. In the passive matrix type, since a complex process is notperformed except that a transparent conductive film is formed and thenetched to form row and column wiring patterns, a glass substrate and aplastic substrate can be used. On the other hand, in the active matrixtype, since a film formation process with relatively high temperature isperformed and the prevention of an active ion such as sodium isrequired, it is necessary to use a glass substrate having an extremelylow alkali concentration.

Thus, in a conventional matrix type display device, except for a specialdevice, it is necessary to provide the display device with asemiconductor integrated circuit (a peripheral driver circuit or a barcircuit) for driving a matrix circuit. Such a circuit is mounted byusing tape automated bonding (TAB) or chip on glass (COG). However,since it has a large scale matrix with, for example, about severalhundred lines, the number of terminals in an integrated circuit isextremely large. Since a driver circuit is constructed by arectangular-shaped integrated circuit (IC) package and a semiconductorchip, it is necessary to lead wirings in order to connect theseterminals to electrical wirings on a substrate. Therefore, an area ofperipheral portion cannot be neglected in comparison with a displayscreen. That is, this area is large relatively.

To solve the problem, a method for forming a driver circuit on a longand narrow substrate (stick or stick crystal) having substantially thesame length as a side of a matrix circuit and then connecting the drivercircuit to terminals of the matrix circuit is disclosed in JapanesePaten Application Open No. 7-14880. Since a width of about 2 mm issufficient for the driver circuit, such arrangement is possible. Thus,an area on the substrate can be almost used as a display screen.

In this state, when a matrix circuit has a large area, since a circuitcannot be formed on a silicon wafer, it is necessary to form it on aglass substrate or the like. Thus, an active element disposed in thepixel electrode on a semiconductor circuit formed on a glass substrateor the like is a TFT using a crystalline semiconductor or an amorphoussemiconductor.

With respect to the stick crystal, a thickness of a substrate for adriver circuit suppresses miniaturization of the whole display device.It is possible that a thickness of a substrate is set to 0.3 mm in orderto obtain a thinner display device, by optimizing a kind of a substrateand a process. From a strength required in a producing process, it isdifficult to set a thickness of the stick crystal to 0.5 mm or less.

When a kind of the stick crystal is different from that of the substrateof the display device, a defect may occur in a circuit by a differenceof thermal expansion or the like. In particular, when a plasticsubstrate is used in the display device, this occurs remarkably. This isbecause that, it is substantially impossible from a view of heatresistance that plastic is used as a substrate of the stick crystal.Also, since the formed semiconductor integrated circuit is thin, wiringsto be connected to the semiconductor integrated circuit is disconnected(broken) at a large step portion of end portions of the semiconductorintegrated circuit or a wiring resistance becomes high, so that aproduct yield of the whole device and reliability are reduced.

In the passive matrix type liquid crystal display device, a firstplurality of strip type electrode wirings made of a transparentconductive film are provided on a first substrate and extended to afirst direction. A second plurality of electrode wirings made of atransparent conductive film are provided on a second substrate andextended to a direction substantially perpendicular to the firstdirection. The first electrode wirings are provided to be opposite tothe second electrode wiring through spacers scattered between the firstand second substrates. A liquid crystal material is filled between thefirst and second electrode wirings and sealed by mainly a seal material(member) which is provided in periphery of a region that the firstsubstrate is opposite to the second substrate. A peripheral drivercircuit, which is connected to the first and second electrode wiringsand controls pixels formed by these electrode wirings and the liquidcrystal material, is provided outside the region that the firstsubstrate is opposite to the second substrate.

In the passive matrix type liquid crystal display device, a complexprocess is not performed except that a transparent conductive film isformed on a substrate and then etched to form strip type electricalwirings and a temperature that the substrate is to be processed is low.Thus, a glass substrate and a plastic substrate can be used as the firstand second substrates.

In an active matrix driver type liquid crystal display device, a firstsubstrate in which an active matrix circuit is provided is disposed tobe opposite to a second substrate (an opposite substrate) that anopposite electrode of a transparent electrode is provided on the wholesurface, through spacers scattered on the first substrate. A liquidcrystal material is sealed by mainly a seal material which is providedin periphery of a region that the first substrate is opposite to thesecond substrate. In the active matrix circuit, pixel electrodesconnected to TFTs are disposed in a plurality of matrix forms. Outsidethe region that the first substrate is opposite to the second substrate,a source driver circuit and a gate driver circuit are provided as aperipheral driver circuit for driving the active matrix circuit.

In a conventional matrix type liquid display device, the peripheraldriver circuit is formed by using a semiconductor integrated circuit andmounted by using TAB or COG. However, the number of electrode wiringsfor constructing a display screen is several hundreds or more. Since adriver circuit is an IC package and a semiconductor chip, it isnecessary to lead wirings in order to connect these terminals toelectrical wirings on a substrate. Therefore, an area of peripheralportion cannot be neglected in comparison with a display screen.

To solve the above problem, there is a method forming directly asemiconductor integrated circuit using TFTs on a substrate except aregion in that the first substrate is opposite to the second substrateand pixels are formed. Also, there is a method for obtaining thesemiconductor integrated circuit by forming directly a driver circuit ona substrate on which a silicon thin film is deposited using anintegrated circuit producing technique. In another method, ansemiconductor integrated circuit using TFTs is formed on othersupporting substrate by using the same technique, and then peeled toadhere it on the first and second substrates, or adhered to thesubstrate before removing an original supporting substrate.

In a liquid crystal display device having such a structure, it isnecessary to provide a protective film made of an organic resin and asilicon nitride system substance in order to prevent the semiconductorintegrated circuit from contaminating due to an impurity such asmoisture, dust, sodium. However, when such a structure is used, stressdue to the protective film acts to the TFTs constructing thesemiconductor integrated circuit. Thus, a density of a recombinationcenter of silicon in the TFT is increased and various characteristicssuch as threshold voltage of the TFT are changed. Also, a characteristicof the TFT constructing the semiconductor integrated circuit is changedby influence due to a pressure applied from an external after the liquidcrystal display device is completed.

To solve the above problem, an example of a conventional active matrixtype liquid crystal display device is shown in FIG. 12. In FIG. 12, anactive matrix circuit 305 including pixel electrodes (not shown), asource driver circuit 303 and a gate driver circuit 304 are provided ona first substrate 301. An opposite (counter) electrode opposite to thepixel electrodes is provided on a whole surface of a second substrate(counter substrate) 302. Spacers (not shown) are scattered on the firstsubstrate 301. Between both electrodes a liquid crystal material 306 isfilled and sealed by a seal material 307.

In FIG. 12, not only the active matrix circuit 305 but also the sourcedriver circuit 303 and the gate driver circuit 304 which are aperipheral driver circuit are opposite to the counter substrate to be incontact with the liquid crystal material 306. That is, by the liquidcrystal material 306, TFTs constructing the peripheral driver circuitare protected. This structure is disclosed in Japanese PatentApplication Open No. 5-66413, for example.

In the liquid crystal display device, spacers which have a sphericalshape, a stick shape, an angular shape or the like between thesubstrates and are made of a hard material such as silica are scattereduniformly, to maintain an interval between two substrates. Each spacerhas a diameter corresponding to the same length as an interval betweenthe substrates. The diameter is about 3 μm to 8 μm in a display deviceusing a nematic liquid crystal, and 1 μm to 4 μm in a display deviceusing a smectic liquid crystal. The number of the spacers is about 50 to1000 per one pixel in a case wherein a size of one pixel is several 10μm square to several 100 μm square.

In the peripheral driver circuit, a large number of TFTs are providedextremely adjacent to one another. Thus, in the liquid crystal displaydevice of FIG. 12, since the peripheral driver circuit is providedwithin a liquid crystal region, if external stress is applied to thesubstrates, the peripheral driver circuit may be broken by the spacersprovided between the substrates. Thus, the peripheral driver circuit donot operate regularly, a point defect and a line defect occur andfurther a display may be impossible, so that reliability and durabilityof the liquid crystal display device are reduced. Such a phenomenonoccurs remarkedly in the liquid crystal display device using a plasticsubstrate which is modifiable by external stress.

SUMMARY OF THE INVENTION

The object of the present invention is to solve the problem with respectto the stick crystal and to obtain a small and light-weight displaydevice.

In the present invention, only a semiconductor integrated circuitequivalent to the stick crystal is connected mechanically andelectrically on a substrate of a display device to thin a driver circuitportion. In this state, it is characterized in that a cross section ofthe semiconductor integrated circuit portion becomes a taper shape thatis wide in a connection portion to the display device and become narrowas it is apart therefrom. In such a structure, there is no vertical stepand disconnection of an electrical wiring does not occur easily. Also,since electrical connection is performed by heating treatment in a lump,thereby to obtain high throughput.

Also, to obtain a small and light-weight liquid crystal display deviceby providing a peripheral driver circuit for controlling display pixelsand electrode wirings in a region in which a liquid crystal is injected,the object of the present invention is to prevent the peripheral drivercircuit and TFTs constructing the peripheral driver circuit frombreaking due to stress application to the substrates and to improvereliability and durability of the liquid crystal display device.

A basic structure of a display device according to the present inventionis as follows. That is, a first substrate includes electrical wiringsand a long and narrow semiconductor integrated circuit which has TFTsand is connected electrically to the electrical wirings, and a secondsubstrate includes a transparent conductive film on a surface thereof. Asurface of the first substrate that the electrical wirings are formed isopposite to the transparent conductive film on the second substrate.Thus, as the stick crystal disclosed in Japanese Paten Application OpenNo. 7-14880, the semiconductor integrated circuit has substantially thesame length as one side of a display screen (i.e., a matrix circuit) ofthe display device and is obtained by peeling it from another substrateand then forming it on the first substrate.

In the passive matrix type, a first substrate includes first electricalwirings of a plurality of transparent conductive films extended to afirst direction and a first long and narrow semiconductor integratedcircuit having TFTs which is connected to the first electrical wiringsand extended to a second direction substantially vertical to the firstdirection, and a second substrate includes second electrical wirings ofa plurality of transparent conductive films extended to the seconddirection and a second semiconductor integrated circuit having TFTswhich is connected to the second electrical wirings and extended to thefirst direction. The first and second substrates in the display deviceare arranged so that the first electrical wirings are opposite to thesecond electrical wirings. The first and second semiconductor integratedcircuits are obtained by peeling them from another substrate and thenforming them on the first and second substrates.

In the active matrix type, a first substrate includes a first pluralityof electrical wirings extended to a first direction and a firstsemiconductor integrated circuit having TFTs which is connected to thefirst electrical wirings and extended to a second directionsubstantially vertical to the first direction, a second plurality ofelectrical wirings extended to the second direction, and a secondsemiconductor integrated circuit having TFTs which is connected to thesecond electrical wirings and extended to the first direction, and asecond substrate includes a transparent conductive film on a surfacethereof. The first and second substrates in the display device arearranged so that the first and second electrical wirings on the firstsubstrate are opposite to the transparent conductive film on the secondsubstrate. The first and second semiconductor integrated circuits areobtained by peeling them from another substrate and then forming them onthe first substrate.

A method for forming a semiconductor integrated circuit having TFTs on asubstrate, peeling the formed circuit from the substrate and adheringthe peeled circuit on another substrate (or removing the substrate afteradhering the circuit on another substrate) has been known as a siliconon insulator (SOI) technique. The technique disclosed in Japanese PatentApplication Open No. 6-504139, another known technique or a techniqueused in an embodiment described below may be used.

FIGS. 1A and 1B show an example of a cross section of a passive matrixtype display device. FIG. 1A is a cross section obtained at a relativelylow magnification. The left side shows a driver circuit portion 1 formedon a semiconductor integrated circuit, and the left shows a matrixportion 2. A semiconductor integrated circuit 6 having a taper-shapedcross section is fixed mechanically on a substrate 3 by a resin 5. Apattern of an electrical wiring 4 made of a transparent conductive filmor the like is formed and at the same time an electrical connection isperformed. FIG. 1B is obtained by magnifying a region enclosed by a dotline in FIG. 1A. The semiconductor integrated circuit 6 has a structurethat an N-channel type TFT 7 and a P-channel type TFT 8 are disposedbetween a base insulating film 9, an interlayer insulator 10 and apassivation film 11 of silicon oxide or the like.

With respect to a contact portion of a semiconductor integrated circuitand a wiring electrode, a wiring may be patterned after thesemiconductor integrated circuit is fixed on a substrate. As shown inFIG. 3A, a semiconductor integrated circuit 34 having a metal wiring 33may be fixed on a substrate 40 having an electrical wiring 31 of atransparent conductive film or the like in advance and then electricalconnection may be performed. FIGS. 3B and 3C are magnification views ofconnection portions. The electrical connection is performed by a methodfor using an anisotropic conductive adhesive 32 in FIG. 3B or a methodfor crimping the metal wiring 33 in a bump 35 disposed on a wiringelectrode 31 in advance in FIG. 3C.

FIGS. 7A and 7B show another example of a cross section of a passivematrix type display device. FIG. 7A is a cross section obtained at arelatively low magnification. The left side shows a driver circuitportion 111 formed on a semiconductor integrated circuit, and the leftshows a matrix portion 112. A metal wiring 114 and a semiconductorintegrated circuit 116 are fixed mechanically on a substrate 113 by aresin 115.

An overlapping portion of an electrical wiring 122 made of a materialsuch as a transparent conductive film formed on the substrate 113 andthe metal wiring 114 is heated by laser irradiation and then melted, toperform electrical connection. At this time, it is desired that themetal wiring 114 is melted easily. Thus, it is preferable to use a metalsuch as an indium tin oxide (ITO) having a low melting point.

FIG. 7B is obtained by magnifying a region enclosed by a dot line inFIG. 7A. The semiconductor integrated circuit 116 has a structure thatan N-channel type TFT 117 and a P-channel type TFT 118 are disposedbetween a base insulating film 119, an interlayer insulator 120 and apassivation film 121 of silicon oxide or the like.

With respect to a contact portion of the metal wiring 114 and the wiringelectrode 122, in addition to a laser melting method, in FIG. 8A, asemiconductor integrated circuit 134 having a metal wiring 133 may befixed on a substrate 140 having an electrical wiring 131 of atransparent conductive film or the like by using an anisotropicconductive adhesive 135 and then electrical connection may be performedby heating and crimping. FIGS. 8B and 8C are magnification views ofconnection portions. In the connection using an anisotropic conductiveadhesive 135 (FIG. 8B), the metal wiring 133 is connected electricallyto the electrical wiring 131 by using conductive particles 136 in theanisotropic conductive adhesive 135. In FIG. 8C, a method for disposinga bump 137 made of a metal having a low melting point on the wiringelectrode 131 in advance and then melting the bump 137 by heating toelectrically connect the electrical wiring 131 to the metal wiring 133can be used.

A schematic order of processes for producing such a passive matrix typedisplay device is shown in FIGS. 2A to 2G. A large number ofsemiconductor integrated circuits (peripheral driver circuits) 22 areformed on a desired substrate 21. (FIG. 2A)

The substrate 21 having the circuits 22 is divided to obtain stickcrystals 23 and 24. Electrical characteristics in the obtained stickcrystals are tested before performing next process, to select a goodproduct. (FIG. 2B)

The stick crystals 23 and 24 are adhered on surfaces 26 and 28 ofanother substrates 25 and 27 in which patterns of wirings made of atransparent conductive film are formed, by the SOI technique, andsemiconductor integrated circuits 29 and 30 on the stick crystals 23 and24 are connected electrically to the wirings. (FIGS. 2C and 2D)

The stick crystals 23 and 24 are peeled so as to remain only thesemiconductor integrated circuits 29 and 30 on the surfaces 26 and 28 ofthe substrates 25 and 27. (FIGS. 2E and 2F)

The obtained substrates are opposed to one another, so that a passivematrix type display device is obtained. A surface 26 is a reversesurface of the surface 26, i.e., a surface on which a wiring pattern isnot formed. (FIG. 2G)

In the above case, a row stick crystal (a stick crystal for a drivercircuit for driving a row wiring) and a column stick crystal (a stickcrystal for a driver circuit for driving a column wiring) are dividedfrom the same substrate 21. However, these stick crystals may be dividedfrom another substrate. Although a passive matrix type display device isshown in FIGS. 2A to 2G, the same process may be performed for an activematrix type display device. A case wherein a material such as a film isformed as a substrate is shown in an embodiment.

According to the present invention, there is provided a liquid crystaldisplay device includes a first substrate in which a passive matrixcircuit and a peripheral driver circuit are provided, a second substratewhich is provided to be opposite to the first substrate, includes apassive matrix circuit and a peripheral driver circuit and has at leasta size corresponding to the passive matrix circuit and the peripheraldriver circuit, spacers provided between the first and second substratesto maintain a desired substrate interval, a seal material formed outsideat least the passive matrix circuits and the peripheral driver circuitsin the first and second substrates, and a liquid crystal material filledinside a region enclosed by the seal material, wherein a protective filmformed on the peripheral driver circuit has substantially a thicknessequivalent to an interval between the substrates which is formed by thespacers.

According to the present invention, there is provided a liquid crystaldisplay device includes a first substrate in which an active matrixcircuit and a peripheral driver circuit are provided, a second substratewhich is provided to be opposite to the first substrate and has at leasta size corresponding to the active matrix circuit and the peripheraldriver circuit, spacers provided between the first and second substratesto maintain a desired substrate interval, a seal material formed outsideat least the active matrix circuits and the peripheral driver circuitsin the first and second substrates, and a liquid crystal material filledinside a region enclosed by the seal material, wherein a protective filmformed on the peripheral driver circuit has substantially a thicknessequivalent to an interval between the substrates which is formed by thespacers.

FIG. 13 shows an example of a liquid crystal display device according tothe present invention. In FIG. 13, a first substrate 501 made of glass,plastic or the like and a second substrate 502 which is a countersubstrate are provided to be opposite to one another. A counterelectrode (not shown) is provided inside the second substrate 502.

On the first substrate 501, a large number of electrode wirings made ofa transparent conductive film and a peripheral driver circuit 503connected to the electrode wirings are provided. Also, on the secondsubstrate 502, a large number of electrode wirings made of a transparentconductive film and a peripheral driver circuit 504 connected to theelectrode wirings are provided.

In a region outside the electrode wirings made of the transparentconductive film and the peripheral driver circuits 503 and 504 in thefirst and second substrates 501 and 502, a seal material 507 isprovided, and a liquid crystal material 506 which is injected from aliquid crystal inlet (not shown) is filled. A plurality of spacers areprovided in a region that the liquid crystal material 506 is injected.

On the peripheral driver circuits 503 and 504, protective films 510 and511 are provided. A thickness of the protective films 510 and 511 issubstantially the same as an interval between the substrates 501 and 502which is formed by the spacers. Note that numeral 505 represents displaypixel electrodes and numeral 509 represents external connectionterminals.

FIG. 14 shows cross section along a line A-A′ in FIG. 13. The protectivefilm 510 is provided on the peripheral driver circuit 503. Also, betweenthe first and second substrates, spacers 401 having a spherical shape isscattered uniformly.

In the present invention, since the protective film 110 provided on theperipheral driver circuit 503 in the substrate 501 has a thicknesssubstantially equivalent to an interval between the substrates which isformed by the spacers, a concentration of local stress due to externalstress 402 can be suppressed and breaking of the peripheral drivercircuit 103 can be prevented.

A schematic order of processes for producing such a display device isshown in FIGS. 2A to 2G, as described above. In this case, the stickcrystals (stick substrates) 23 and 24 in which peripheral drivercircuits are formed are obtained by cutting the same substrate 21.However, these stick crystals may be obtained by different substrates.Although a passive matrix type display device is shown in FIGS. 2A to2G, the same process may be performed for an active matrix type displaydevice. Further, since a driver circuit is formed on another substrateand then adhered, a material such as a plastic film can be used as asubstrate.

According to the present invention, in a liquid crystal display device,a matrix circuit and a peripheral driver circuit are provided in aliquid crystal region, and a protective film having a thicknesssubstantially equivalent to a size of the spacers scattered in theliquid crystal region is provided on the peripheral driver circuit, sothat breaking of TFTs constructing the peripheral driver circuit due tostress application to the substrates can be prevented and an intervalbetween the substrates can be maintained to be constant. Thus,reliability and durability of the liquid crystal display device can beimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show a cross section structure according to the presentinvention;

FIGS. 2A to 2G show a producing method of a display device of thepresent invention;

FIGS. 3A to 3C show an example of a cross section structure of a displaydevice of the present invention;

FIGS. 4A to 4C show an example of a producing process of a semiconductorintegrated circuit used in the present invention;

FIGS. 5A to 5D show a process for adhering a semiconductor integratedcircuit to a substrate of a display device;

FIGS. 6A and 6B show an example of a producing process of asemiconductor integrated circuit used in the present invention;

FIGS. 7A and 7B show another example of a cross section structure of adisplay device of the present invention;

FIGS. 8A to 8C show a cross section structure according to the presentinvention;

FIGS. 9A to 9C show another example of a producing process of asemiconductor integrated circuit used in the present invention;

FIGS. 10A to 10D a process for adhering a semiconductor integratedcircuit to a substrate of a display device;

FIGS. 11A and 11B show an example of a process of electrical connectionof a wiring in the present invention;

FIG. 12 shows a conventional liquid crystal display device;

FIG. 13 shows a liquid crystal display device according to the presentinvention;

FIG. 14 is a cross section view in a line A-A′ of FIG. 13;

FIGS. 15A to 15C show a producing process of a stick substrate used inthe present invention; and

FIGS. 16A to 16D show a process for adhering a peripheral driver circuiton the stick substrate to another substrate in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

The embodiment shows a schematic producing process for one substrate ina passive matrix type liquid crystal display device, using FIGS. 4A to5D. FIGS. 4A to 4C show a schematic process for forming a driver circuiton a stick crystal, and FIGS. 5A to 5D show a schematic process forforming the driver circuit on a substrate in a liquid crystal displaydevice.

A silicon film having a thickness of 3000 Å is deposited as a peelinglayer 51 on a glass substrate 50. Since this silicon film is etched whena circuit formed thereon is peeled from the substrate, there is noproblem almost with respect to a film quality, so that the silicon filmmay be deposited by a method that mass-production is possible. Thesilicon film may be amorphous or crystalline and include anotherelement.

As the glass substrate, a glass (containing no alkali or alkali at a lowconcentration) or a quartz glass such as Corning 7059, Corning 1737, NHtechnoglass NA 45, NH technoglass NA 35 or Japan electric glass OA2 maybe used. When a quartz glass is used, there is a problem in its cost.However, since, in the present invention, an area used in one liquidcrystal display device is extremely small, a cost per unit issufficiently low.

A silicon oxide film 53 having a thickness of 200 nm is deposited on thepeeling layer 51. Since the silicon oxide film 53 is used as a basefilm, it is necessary to pay sufficient attention to its formation. By aknown method, crystalline island silicon regions (silicon islands) 54and 55 are formed. A thickness of these silicon islands 54 and 55influence characteristics of a necessary semiconductor circuit. Ingeneral, it is preferable to be a thin film. In the embodiment, thethickness is 40 to 60 nm.

To obtain crystalline silicon, a method for irradiating an intense lightsuch as a laser into amorphous silicon (a laser annealing method) or amethod for making solid phase growth (crystallization) by thermalannealing (a solid phase growth (crystallization) method) is used. Inusing the solid phase growth method, as disclosed in Japanese PatentApplication Open No. 6-244104, when a catalytic element such as nickelis added to silicon, a crystallization temperature can be reduced and anannealing time can be shortened. Also, as disclosed in Japanese Patentapplication Open No. 6-318701, silicon crystallized by the solid phasegrowth method may be laser-annealed. A method to be used may bedetermined in accordance with characteristics of a necessarysemiconductor integrated circuit, a heat-resistance temperature of asubstrate and the like.

By plasma chemical vapor deposition (plasma CVD) or thermal CVD, asilicon oxide having a thickness of 120 nm is deposited as a gateinsulating film 56, and then gate electrode-wirings 57 and 58 usingcrystalline silicon having a thickness of 500 nm are formed. The gateelectrode-wirings may be a metal such as aluminum, tungsten or titanium,or siliside thereof. When metal gate electrode-wirings 57 and 58 areformed, as disclosed in Japanese Patent Application No. 5-26/66/ or6-338612, an upper or a side surface of the gate electrode-wirings maybe coated with an anodic oxide. A material constructing the gateelectrode-wirings 57 and 58 may be determined in accordance withcharacteristics of a necessary semiconductor circuit, a heat-resistancetemperature of a substrate and the like. (FIG. 4A)

In a self-alignment, an N-type and a P-type impurities are introducedinto the silicon islands 54 and 55 by ion doping or the like, to formN-type regions 59 and P-type regions 60. An interlayer insulator 61 (asilicon oxide film having a thickness of 500 nm) is deposited by a knownmethod, and then contact holes are formed therein, to form aluminumalloy wirings 62 to 64. (FIG. 48)

A polyimide film 70 is formed as a passivation film on those films byadding varnish and then curing it. In the embodiment, Photoneath UR-3800of Toray Industries Inc. is used. Addition is performed by a spinner(not shown). An addition condition may be determined in accordance witha desired film thickness. The polyimide film 70 having a thickness ofabout 4 μM is formed at 3000 rpm for 30 seconds. After drying, exposureand development are performed. By selecting a desired condition, adesired taper shape can be obtained. The film is than cured byprocessing at 300° C. in an atmosphere containing nitrogen. (FIG. 4C)

A transfer substrate 72 is adhered to the semiconductor integratedcircuit by a resin 71. It is desired that the transfer substrate 72 hasa strength and a flat surface to hold the integrated circuitimpermanently. Thus, glass, plastic or the like can be used. Since thetransfer substrate 72 is peeled later, it is preferable that the resin71 is a removable material. Also, as the resin 71, a removable materialsuch as an adhesive may be used. (FIG. 5A)

The processed substrate is left within air flow of a mixture gas offluorine trichloride (ClF₃) and nitrogen. A flow rate of fluorinetrichloride and nitrogen is set to 500 sccm. A reaction process is 1 to10 Torr. A temperature is a room temperature. It has been known thatfluorine halide such as fluorine trichloride has a characteristic forselectively etching silicon. On the other hand, silicon oxide is notalmost etched. Thus, the peeling layer made of silicon is etched inaccordance with an elapse. However, the base film 53 made of siliconoxide is not almost etched, so that a TFT element is not damaged. Whenfurther elapsing a time, the peeling layer 51 is etched completely,thereby to peel the semiconductor integrated circuit completely. (FIG.5B)

The peeled semiconductor integrated circuit is adhered to a substrate 75of a liquid crystal display device by a resin 76 and then the transfersubstrate 72 is removed. (FIG. 5C)

Thus, a transfer of the semiconductor integrated circuit to thesubstrate 75 of the liquid crystal display device is completed. Thesubstrate of the liquid crystal display device is polyether sulfate(PBS) having a thickness of 0.3 mm.

By sputtering, an indium tin oxide (ITO) film 80 having a thickness of100 nm is formed. The ITO film is a transparent conductive oxide andpatterned to complete electrical connection between the electricalwirings and the semiconductor integrated circuit. (FIG. 5D)

As a result, the formation of the semiconductor integrated circuit onone substrate of the liquid crystal display device is completed. Theliquid crystal display device is completed by using the obtainedsubstrate.

Embodiment 2

The embodiment shows a schematic process for producing a semiconductorintegrated circuit on a stick crystal. The embodiment will be explainedusing FIGS. 6A and 6B.

In FIG. 6A, a peeling layer 102 made of silicon is formed on a substrate101, and then a driver circuit (a semiconductor integrated circuit) 100having TFTs is formed on the peeling layer 102. These are formed by thesame process as in Embodiment 1. A silicon oxide film is formed as apassivation film. In the embodiment, two-layer silicon oxide films 103and 104 are formed by plasma CVD. The first silicon oxide film 103 isformed by applying a relatively high power, and the second silicon oxidefilm 104 is formed by a relatively low power. A thickness of the firstsilicon oxide film 103 is 100 to 500 nm, and a thickness of the secondsilicon oxide film 104 is 500 to 1000 nm.

After a resist 105 for patterning is formed, the substrate having alaminate is immersed in a 1/10 hydrofluoric acid solution to etch thesilicon oxide films 103 and 104. At this time, an etching rate of thefirst silicon oxide film 103 formed by applying the relatively highpower is low than that of the second silicon oxide film 104 formed byapplying the relatively low power. As a result, the second silicon oxidefilm 104 is undercut greatly. (FIG. 6B)

Finally, by peeling the resist, a semiconductor integrated circuithaving a taper-shaped cross section is completed.

In the embodiment, the two-layer silicon oxide films 103 and 104 for apassivation film are used. Three-layers or more may be used. Also, bychanging a film formation condition successively, a film may be used sothat an etching rate becomes large in a direction from a lower layer toan upper layer. Further, a material such as silicon nitride having thesame effect or a combination thereof can be used.

In the embodiment, since periphery of end portions of the insulatingfilm 70 covering the semiconductor integrated circuit 100 has a tapershape, disconnection of a formed wiring in a step portion can beprevented. Also, a product yield and reliability can be improved.

Embodiment 3

The embodiment shows a schematic producing process for one substrate ina passive matrix type liquid crystal display device, using FIGS. 9A to10D. FIGS. 9A to 9C show a schematic process for forming a drivercircuit on a stick crystal, and FIGS. 10A to 10D show a schematicprocess for forming the driver circuit on a substrate in a liquidcrystal display device.

A silicon film having a thickness of 3000 Å is deposited as a peelinglayer 151 on a glass substrate 150. Since this silicon film is etchedwhen a circuit formed thereon is peeled from the substrate, there is noproblem almost with respect to a film quality, so that the silicon filmmay be deposited by a method that mass-production is possible. Also, thesilicon film used as the peeling layer 151 may be amorphous orcrystalline and include another element.

As the glass substrate 150, a glass (containing no alkali or alkali at alow concentration) or a quartz glass such as Corning 7059, Corning 1737,NH technoglass NA 45, NH technoglass NA 35 or Japan electric glass OA2may be used. When a quartz glass is used, there is a problem in itscost. However, since, in the present invention, an area used in oneliquid crystal display device is extremely small, a cost per unit issufficiently low.

A silicon oxide film 153 having a thickness of 200 nm is deposited onthe peeling layer 151. Since the silicon oxide film 153 is used as abase film, it is necessary to pay sufficient attention to its formation.By a known method, crystalline island silicon regions (silicon islands)154 and 155 are formed. A thickness of the silicon islands 154 and 155influence characteristics of a necessary semiconductor circuit. Ingeneral, it is preferable to be a thin film. In the embodiment, thethickness is 40 to 60 nm.

To obtain crystalline silicon, a method for irradiating an intense lightsuch as a laser into amorphous silicon (a laser annealing method) or amethod for making solid phase growth (crystallization) by thermalannealing (a solid phase growth (crystallization) method) is used. Inusing the solid phase growth method, as disclosed in Japanese PatentApplication Open No. 6-244104, when a catalytic element such as nickelis added to silicon, a crystallization temperature can be reduced and anannealing time can be shortened. Also, as disclosed in Japanese Patentapplication Open No. 6-318701, silicon crystallized by the solid phasegrowth method may be laser-annealed. A method to be used may bedetermined in accordance with characteristics of a necessarysemiconductor integrated circuit, a heat-resistance temperature of asubstrate and the like.

By plasma CVD or thermal CVD, a silicon oxide having a thickness of 120nm is deposited as a gate insulating film 156, and then gateelectrode-wirings 157 and 158 using crystalline silicon having athickness of 500 nm are formed. The gate electrode-wirings 157 and 158may be a metal such as aluminum, tungsten or titanium, or silisidethereof. When metal gate electrode-wirings are formed, as disclosed inJapanese Patent Application No. 5-267667 or 6-338612, an upper or a sidesurface of the gate electrode-wirings may be coated with an anodicoxide. A material constructing the gate electrode-wirings 157 and 158may be determined in accordance with characteristics of a necessarysemiconductor circuit, a heat-resistance temperature of a substrate andthe like. (FIG. 9A)

In a self-alignment, an N-type and a P-type impurities are introducedinto the silicon islands 154 and 155 by ion doping or the like, to formN-type regions 159 and P-type regions 160 in the silicon islands 154 and155. An interlayer insulator 161 (a silicon oxide film having athickness of 500 nm) is deposited by a known method, and then contactholes are formed therein, to form aluminum alloy wirings 162 to 164.(FIG. 9B)

A polyimide film 170 is formed as a passivation film by adding varnishand then curing it. In the embodiment, Photoneath UR-3800 of TorayIndustries Inc. is used. Addition is performed by a spinner (not shown).An addition condition may be determined in accordance with a desiredfilm thickness. The polyimide film 170 having a thickness of about 4 μmis formed at 3000 rpm for 30 seconds. After drying, exposure anddevelopment are performed. By selecting a desired condition, a desiredpattern can be obtained. Then, the film is cured by processing at 300°C. in an atmosphere containing nitrogen. A metal wiring 190 of aluminumis formed thereon by sputtering. (FIG. 9C)

A transfer substrate 172 is adhered to the semiconductor integratedcircuit by a resin 171. It is desired that the transfer substrate 172has a strength and a flat surface to hold the integrated circuitimpermanently. Thus, glass, plastic or the like can be used. Since thetransfer substrate 172 is peeled later, it is preferable that the resin71 is a removable material. Also, as the resin 71, a removable materialsuch as an adhesive may be used. (FIG. 10A)

The processed substrate is left in air flow of a mixture gas of fluorinetrichloride (ClF₃) and nitrogen. A flow rate of fluorine trichloride andnitrogen is 500 sccm. A reaction process is 1 to 10 Torr. A temperatureis a room temperature. It has been known that fluorine halide such asfluorine trichloride has a characteristic for selectively etchingsilicon. Silicon oxide is not almost etched. Thus, the peeling layer 151made of silicon is etched in accordance with an elapse. Since the basefilm 153 made of silicon oxide is not almost etched, a TFT element isnot damaged. When further elapsing a time, the peeling layer 151 isetched completely, thereby to peel the semiconductor integrated circuitcompletely. (FIG. 10B)

The peeled semiconductor integrated circuit is adhered to a substrate175 of a liquid crystal display device by a resin 176 and then thetransfer substrate 172 is removed. (FIG. 10C)

Thus, a transfer of the semiconductor integrated circuit to thesubstrate of the liquid crystal display device is completed. Thesubstrate of the liquid crystal display device is polyether sulfate(PES) having a thickness of 0.3 mm.

An overlapping portion of a wiring electrode 180 and the metal wiring190 which are formed on the substrate of the liquid crystal displaydevice is irradiated with a YAG laser 185 and then heated, to performelectrical connection. (FIG. 10D)

As a result, the formation of the semiconductor integrated circuit onone substrate of the liquid crystal display device is completed. Theliquid crystal display device is completed by using the obtainedsubstrate.

Embodiment 4

The embodiment shows a schematic process for electrically connecting awiring on a substrate of a liquid crystal display device to a metalwiring in a semiconductor integrated circuit using FIGS. 11A and 11B.FIGS. 11A and 11B are magnification views of a connection portion of awiring electrode on a substrate of a liquid crystal display device and ametal wiring of a semiconductor integrated circuit.

A wiring electrode 201 made of a transparent conductive film is formedon a substrate 200 of a liquid crystal display device by sputtering.Further, a pad 202 made of a metal having a low melting point is formedin a portion to be electrically connected to a semiconductor integratedcircuit by sputtering.

Using the method as described in Embodiment 1, a semiconductorintegrated circuit and a metal wiring which are formed on anothersubstrate 203 are fixed mechanically through an adhesive 204. (FIG. 11A)

An overlapping portion of the metal wiring on another substrate 203 andthe pad 202 is melted by a YAG laser 206, to complete an electricalconnection 208. (FIG. 11B)

In the embodiment, a laser is irradiated from a position over the metalwiring of another substrate 203. In a case wherein a laser is irradiatedfrom a position under the substrate 200, the same effect is alsoobtained.

Embodiment 5

The embodiment shows a schematic producing process for one substrate ina passive matrix type liquid crystal display device, using FIGS. 15A to16D. FIGS. 15A to 15C show a schematic process for forming a peripheraldriver circuit on a stick substrate, and FIGS. 16A to 16D show aschematic process for forming the peripheral driver circuit on asubstrate in a liquid crystal display device.

A silicon film having a thickness of 3000 Å is deposited as a peelinglayer 732 on a glass substrate 731. Since this silicon film is etchedwhen a circuit formed thereon is peeled from the substrate, there is noproblem almost with respect to a film quality, so that the silicon filmmay be deposited by a method that mass-production is possible. Thesilicon film may be amorphous or crystalline.

As the glass substrate 731, a glass (containing no alkali or alkali at alow concentration) or a quartz glass such as Corning 7059, Corning 1737,NH technoglass NA 45, NH technoglass NA 35 or Japan electric glass OA2may be used. When a quartz glass is used, there is a problem in itscost. However, since, in the present invention, an area used in oneliquid crystal display device is extremely small, a cost per unit issufficiently low.

A silicon oxide film 733 having a thickness of 5000 Å is deposited onthe peeling layer 732. Since the silicon oxide film 733 is used as abase film, it is necessary to pay sufficient attention to its formation.By a known method, crystalline island silicon regions (silicon islands)734 and 735 are formed. A thickness of these silicon islands 734 and 735influence characteristics of a necessary semiconductor circuit. Ingeneral, it is preferable to be a thin film. In the embodiment, thethickness is 400 to 600 Å.

To obtain crystalline silicon, a method for irradiating an intense lightsuch as a laser into amorphous silicon (a laser annealing method) or amethod for making solid phase growth (crystallization) by thermalannealing (a solid phase growth (crystallization) method) is used. Inusing the solid phase growth method, as disclosed in Japanese PatentApplication Open No. 6-244104, when a catalytic element such as nickelis added to silicon, a crystallization temperature can be reduced and anannealing time can be shortened. Also, as disclosed in Japanese Patentapplication Open No. 6-318701, silicon crystallized by the solid phasegrowth method may be laser-annealed. A method to be used may bedetermined in accordance with characteristics of a necessarysemiconductor integrated circuit, a heat-resistance temperature of asubstrate and the like.

By plasma CVD or thermal CVD, a silicon oxide having a thickness of 1200Å is deposited as a gate insulating film 736, and then gateelectrode-wirings 737 and 738 using crystalline silicon having athickness of 5000 Å are formed. The gate electrode-wirings may be ametal such as aluminum, tungsten or titanium, or siliside thereof. Whenmetal gate electrode-wirings are formed, as disclosed in Japanese PatentApplication No. 5-267667 or 6-338612, an upper or a side surface of thegate electrode-wirings may be coated with an anodic oxide. A materialconstructing the gate electrode-wirings 737 and 738 may be determined inaccordance with characteristics of a necessary semiconductor circuit, aheat-resistance temperature of a substrate and the like. (FIG. 15A)

In a self-alignment, an N-type and a P-type impurities are introducedinto the silicon islands 134 and 135 by ion doping or the like, to formN-type regions 739 and P-type regions 740. An interlayer insulator 741(a silicon oxide film having a thickness of 5000 Å) is deposited by aknown method, and then contact holes are formed therein, to formaluminum alloy wirings 742 to 744. (FIG. 15B)

A silicon nitride film 746 having a thickness of 2000 Å is deposited asa passivation film by plasma CVD, and then a contact hole for the wiring744 of an output terminal is formed therein. By sputtering, an electrode747 made of an ITO film having a thickness of 1000 Å is formed. The ITOfilm is a transparent conductive oxide. Then, a bump 748 made of goldhaving a diameter of about 50 μm and a height of about 30 μm is formedmechanically on the ITO electrode 747. The obtained circuit is dividedto obtain stick substrates each having a desired size. (FIG. 15C)

On the other hand, as shown in FIG. 16A, an ITO electrode 750 having athickness of 1000 Å is formed on a substrate 749 used in a liquidcrystal display device. In the embodiment, the substrate in the liquidcrystal display device is polyether sulfate (PES) having a thickness of0.3 mm. Stress (pressure) are applied to the substrate 749 and the sticksubstrate 731 to adhere to these substrates one another. At this time,the ITO electrode 747 is connected electrically to the ITO electrode 750through the bump 748. (FIG. 16A)

An adhesive 751 which is mixed with a thermally curable organic resin isinjected into a gap between the stick substrate 731 and the substrate749 in the liquid crystal display device. The adhesive 751 may beapplied to a surface of one of the substrates in advance before thestick substrate 731 is crimped to the substrate 749 in the liquidcrystal display device.

By processing at 120° C. for 15 minutes in an atmosphere containingnitrogen in an oven, electric connection and mechanical adhesion betweenthe stick substrate 731 and the substrate 749 are completed. Beforecomplete adhesion, it may be tested whether or not sufficient electricalconnection state is obtained, by a method disclosed in Japanese PatentApplication Open No. 7-14880, and then a main adhesion method may beutilized. (FIG. 16B)

The processed substrates are left within air flow of a mixture gas offluorine trichloride (ClF₃) and nitrogen. A flow rate of fluorinetrichloride and nitrogen is set to 500 sccm. A reaction process is 1 to10 Torr. A temperature is a room temperature. It has been known thatfluorine halide such as fluorine trichloride has a characteristic forselectively etching silicon. On the other hand, silicon oxide is notalmost etched. However, oxides (silicon oxide and ITO) are not almostetched. Also, when a stable oxide film is formed on a surface ofaluminum, since reaction is stopped, etching is not performed.

In the embodiment, a material which is etchable by fluorine trichlorideis the peeling layer (silicon) 732, the silicon islands 734 and 735, thegate electrodes 737 and 738, the aluminum alloy wirings 742 to 744 andthe adhesive 751. With respect to the materials other than the peelinglayer 732 and the adhesive 751, since a material such as silicon oxideis formed outside the materials, fluorine trichloride cannot reach thematerials. Actually, as shown in FIG. 16C, only the peeling layer 732 isetched selectively, thereby to form holes 752.

When a time elapses, the peeling layer 732 is etched completely, so thata bottom surface 753 of the base film 733 is exposed. Therefore, thestick substrate 731 can be separated from a semiconductor circuit. Inetching using fluorine trichloride, since etching is stopped at thebottom surface 753 of the base film 733, the bottom surface 753 isextremely flat. (FIG. 16D)

By such processing, a transfer of the peripheral driver circuit from thestick substrate to one substrate of the liquid crystal display device iscompleted. Then, a polyimide film is formed as a protective film on thetransferred peripheral driver circuit by adding varnish and then curingit. In the embodiment, Photoneath UR-3800 of Toray Industries Inc. isused. Addition is performed by a spinner (not shown). An additioncondition nay be determined in accordance with a desired film thickness.The polyimide film having a thickness of about 5 μm is formed at 2000rpm for 20 seconds. After the addition is performed, drying, exposureand development are performed to remove an unnecessary polyimide. Thefilm is then cured by processing it at 300° C. in an atmospherecontaining nitrogen. It is important that a thickness of the polyimidefilm is set to be substantially the same as a diameter of spacers to beused later. Thus, it can be prevented that the spacers are present onthe peripheral driver circuit. A thickness of the polyimide film may beset to be substantially the same as that of a seal material. However, ingeneral, the thickness of the seal material is determined by thespacers, the thickness of the polyimide film is generally set to be thediameter of the spacers. In a passive matrix type display device, theocher substrate is produced by substantially the same process asdescribed above.

Next, a producing process for a passive matrix type liquid crystaldisplay device is explained below.

The first and second substrates produced by the above processes aresufficiently washed to remove various chemicals such as an etchingsolution, a resist solution and a peeling solution which are used forsurface-processing.

An orientation film is adhered to an electrode region which is made ofITO and constructs pixels. An orientation material is obtained bydissolving, in a solvent such as butyl cellosolve or N-methylpyrrolidone, a polyimide having about 10 weight % of the solvent.

The orientation films adhered to the first and second substrates areheated and cured (baked). Then, rubbing treatment is performed so that asurface of a glass substrate to which the orientation film is adhered isrubbed in a desired direction by using a buff cloth (a fiber such asrayon and nylon) having of a wool length of 2 to 3 mm at a surface andthus fine grooves are formed.

Spherical spacers of a polymer system, a glass system, a silica systemor the like are scattered (dispersed) on one of the first and secondsubstrates. A spacer scattering method includes a wet method forscattering, on a substrate, spacers into which a solvent such as purewater or alcohol is mixed and a dry method for scattering, on asubstrate, spacers without using a solvent. In the embodiment, the drymethod is used.

A resin used as a seal material provided in an outer side of a substrateis applied. The seal material to be used is obtained by dissolving anepoxy resin and a phenol curing agent in a solvent of ethyl cellosolve.An acrylate system resin may be used. Also, a thermal-curable type or aultraviolet-curable type may be used.

By a screen printing method, a seal material is applied and formed onthe first substrate or the second substrate.

After forming the seal material, two glass substrates are adhered to oneanother. As a method for adhering and curing, a heating curing methodfor curing a seal material for about 3 hours by high temperature pressat about 160° C. is used.

A liquid crystal material is injected from a liquid crystal inlet of thepassive matrix type display device produced by adhering the first andsecond substrates, and then the liquid crystal inlet is sealed by usingan epoxy system resin.

Thus, the passive matrix type liquid crystal display device iscompleted.

Embodiment 6

The embodiment shows a schematic producing process for one substrate ina passive matrix type liquid crystal display device, using FIGS. 4A to5D.

As described in Embodiment 1, the silicon film is deposited as thepeeling layer 51 on the glass substrate 50. The silicon oxide film 53 isdeposited as a base film on the peeling layer 51. The crystallinesilicon islands 54 and 55 are formed. Also, by plasma CVD or thermalCVD, the silicon oxide is deposited as the gate insulating film 56, andthen gate electrode-wirings 57 and 58 using crystalline silicon areformed.

An N-type and a P-type impurities are introduced into the siliconislands 54 and 55 by ion doping or the like, to form the N-type regions59 and the P-type regions 60. The interlayer insulator 61 is deposited,and then contact holes are formed therein, to form the aluminum alloywirings 62 to 64.

The polyimide film 70 is formed as a passivation film at 2000 rpm for 25seconds by a spinner. The thickness of the polyimide film 70 is set inaccordance with a diameter of spacers.

The transfer substrate 72 is adhered to the semiconductor integratedcircuit by the resin 71.

The processed substrate is left within air flow of a mixture gas offluorine trichloride and nitrogen. Fluorine halide such as fluorinetrichloride has a characteristic for selectively etching silicon. On theother hand, silicon oxide is not almost etched. Thus, the peeling layermade of silicon is etched in accordance with an elapse. However, thebase film 53 made of silicon oxide is not almost etched, so that a TFTelement is not damaged. When further elapsing a time, the peeling layer51 is etched completely, thereby to peel the semiconductor integratedcircuit completely.

The peeled semiconductor integrated circuit is adhered to a substrate 75of a liquid crystal display device by a resin 76 and then the transfersubstrate 72 is removed. Thus, a transfer of the semiconductorintegrated circuit to the substrate 75 of the liquid crystal displaydevice is completed.

By sputtering, the ITO film 80 is formed. The ITO film is a transparentconductive oxide and patterned to complete electrical connection betweenthe electrical wirings and the semiconductor integrated circuit.

As a result, the formation of the semiconductor integrated circuit onone substrate of the liquid crystal display device is completed. Theliquid crystal display device is completed by using the obtainedsubstrate.

Next, a producing process for a passive matrix type liquid crystaldisplay device is explained below.

The first and second substrates produced by the above processes aresufficiently washed to remove various chemicals such as an etchingsolution, a resist solution and a peeling solution which are used forsurface-processing.

An orientation film is adhered to an electrode region which is made ofITO and constructs pixels. An orientation material is obtained bydissolving, in a solvent such as butyl cellosolve or N-methylpyrrolidone, a polyimide having about 10 weight % of the solvent.

The orientation films adhered to the first and second substrates areheated and cured (baked). Then, rubbing treatment is performed so that asurface of a glass substrate to which the orientation film is adhered isrubbed in a desired direction by using a buff cloth (a fiber such asrayon and nylon) having of a wool length of 2 to 3 mm at a surface andthus fine grooves are formed.

Spherical spacers of a polymer system, a glass system, a silica systemor the like are scattered (dispersed) on one of the first and secondsubstrates. A spacer scattering method includes a wet method forscattering, on a substrate, spacers into which a solvent such as purewater or alcohol is mixed and a dry method for scattering, on asubstrate, spacers without using a solvent. In the embodiment, the drymethod is used.

A resin used as a seal material provided in an outer side of a substrateis applied. The seal material to be used is obtained by dissolving anepoxy resin and a phenol curing agent in a solvent of ethyl cellosolve.An acrylate system resin may be used. Also a thermal-curable type or aultraviolet-curable type may be used.

By a screen printing method, a seal material is applied and formed onthe first substrate or the second substrate.

After forming the seal material, two glass substrates are adhered to oneanother. As a method for adhering and curing, a heating curing methodfor curing a seal material for about 3 hours by high temperature pressat about 160° C. is used.

A liquid crystal material is injected from a liquid crystal inlet of thepassive matrix type display device produced by adhering the first andsecond substrates, and then the liquid crystal inlet is sealed by usingan epoxy system resin.

Thus, the passive matrix type liquid crystal display device iscompleted.

In the present invention, it is possible to use various variations withrespect to a kind, a thickness and a size of a substrate in a displaydevice. For example, as described in Embodiment 1, a extremely thinfilm-shaped liquid crystal display device can be obtained. In this case,the display device may be adhered along a curved surface. Also, since alimitation of a kind of a substrate is relaxed, a material having lightweight and high shock resistance, such as a plastic substrate, can beused, thereby to improve portability.

In particular, by forming periphery of end portions of an insulatingfilm covering a semiconductor integrated circuit into a taper shape, astructure having no disconnection of a wiring in step portion can beformed at formation of wirings or after the formation. thus, reliabilityof a display device can be improved.

Also, since an occupying area a driver circuit is small, a degree offreedom in arrangement of one display device and another display deviceis increased. Typically, since a driver circuit can be arranged in anarea (several mm in width) around a display surface, a display deviceitself is an extremely simple and fashionable product. Its applicationis extended to various fields.

According to the present invention, in a liquid crystal display devicethat a peripheral driver circuit is provided in a liquid crystal regionwherein contamination resistance and humidity resistance of theperipheral driver circuit are improved and an external appearance issimple, breaking of the peripheral driver circuit due to a stresspressure to a substrate can be prevented and a substrate interval can bemaintained constant. In particular, in a liquid crystal display devicein which a plastic substrate modifiable by an external stress is used,breaking of the peripheral driver circuit can be prevented. Thus,reliability and durability of the liquid crystal display device can beimproved further.

Thus, the present invention has an extremely high industrial value.

1. A method of manufacturing a semiconductor device comprising: forminga peeling layer over a first substrate; forming a base film over thepeeling layer; forming a semiconductor device including a thin filmtransistor over the base film, wherein the thin film transistorcomprises a semiconductor film, a gate electrode, a gate insulatingfilm, and a first electrode electrically connected to the semiconductorfilm; sticking a second substrate having a second electrode over thefirst substrate so as to electrically connect the second electrode withthe first electrode; and separating the first substrate from thesemiconductor device at the peeling layer.
 2. A method of manufacturinga semiconductor device according to claim 1, wherein the peeling layercomprises silicon.
 3. A method of manufacturing a semiconductor device1, wherein the second substrate comprises polyether sulfate.
 4. A methodof manufacturing a semiconductor device 1, wherein the first electrodeand the second electrode comprise indium tin oxide.
 5. A method ofmanufacturing a semiconductor device 1, wherein the separating step isconducted by etching the peeling layer.
 6. A method of manufacturing asemiconductor device comprising: forming a peeling layer over a firstsubstrate; forming a base film over the peeling layer; forming asemiconductor device including a thin film transistor over the basefilm, wherein the thin film transistor comprises a semiconductor film, agate electrode, a gate insulating film, and a first electrodeelectrically connected to the semiconductor film; sticking a secondsubstrate having a second electrode over the first substrate so as toelectrically connect the second electrode with the first electrode via ametal bump; and separating the first substrate from the semiconductordevice at the peeling layer.
 7. A method of manufacturing asemiconductor device according to claim 6, wherein the peeling layercomprises silicon.
 8. A method of manufacturing a semiconductor device6, wherein the second substrate comprises polyether sulfate.
 9. A methodof manufacturing a semiconductor device 6, wherein the first electrodeand the second electrode comprise indium tin oxide.
 10. A method ofmanufacturing a semiconductor device 6, wherein the metal bump comprisesgold.
 11. A method of manufacturing a semiconductor device 6, whereinthe separating step is conducted by etching the peeling layer.
 12. Amethod of manufacturing a semiconductor device comprising: forming apeeling layer over a first substrate; forming a base film over thepeeling layer; forming a semiconductor device including a thin filmtransistor over the base film, wherein the thin film transistorcomprises a semiconductor film, a gate electrode, a gate insulatingfilm, and a first electrode electrically connected to the semiconductorfilm; sticking a second substrate having a second electrode over thefirst substrate so as to electrically connect the second electrode withthe first electrode; and injecting an adhesive between the firstelectrode and the second electrode; and separating the first substratefrom the semiconductor device at the peeling layer.
 13. A method ofmanufacturing a semiconductor device according to claim 12, wherein thepeeling layer comprises silicon.
 14. A method of manufacturing asemiconductor device 12, wherein the second substrate comprisespolyether sulfate.
 15. A method of manufacturing a semiconductor device12, wherein the first electrode and the second electrode comprise indiumtin oxide.
 16. A method of manufacturing a semiconductor device 12,wherein the separating step is conducted by etching the peeling layer.17. A method of manufacturing a semiconductor device comprising: forminga peeling layer over a first substrate; forming a base film over thepeeling layer; forming a semiconductor device including a thin filmtransistor over the base film, wherein the thin film transistorcomprises a semiconductor film, a gate electrode, a gate insulatingfilm, and a first electrode electrically connected to the semiconductorfilm; sticking a second substrate having a second electrode over thefirst substrate so as to electrically connect the second electrode withthe first electrode via a metal bump; injecting an adhesive between thefirst electrode and the second electrode; and separating the firstsubstrate from the semiconductor device at the peeling layer.
 18. Amethod of manufacturing a semiconductor device according to claim 17,wherein the peeling layer comprises silicon.
 19. A method ofmanufacturing a semiconductor device 17, wherein the second substratecomprises polyether sulfate.
 20. A method of manufacturing asemiconductor device 17, wherein the first electrode and the secondelectrode comprise indium tin oxide.
 21. A method of manufacturing asemiconductor device 17, wherein the metal bump comprises gold.
 22. Amethod of manufacturing a semiconductor device 17, wherein theseparating step is conducted by etching the peeling layer.